This invention relates in general to certain new and useful improvements in audio fidelity amplifier systems and, more particularly, to audio fidelity amplifier systems which include provision for mixing of a number of input sources and selective equalization of the frequencies in such input sources and output circuits thereof.
In recent years, there have been many advancements in the field of audio fidelity recording and reproducing, both in professional areas and in the so-called "home audio fidelity systems". In the professional area, where audio-fidelity equipment is used, as for example in recording studios, these advances lie in improved recording amplifiers and in mixing facilities, as well as in various forms of frequency equalization facilities. However, these various professional systems are quite expensive and are generally designed only for professional use.
There have also been many advances in the audio fidelity recording and reproducing systems, as for example the so-called "stereophonic amplification systems for home use," that is for use by individuals other than the professionals. Nevertheless, the developments for the so-called "home" stereophonic fidelity market have been relatively limited in terms of versatility of the systems which are available. For example, there are relatively few amplifiers and preamplifiers which even remotely approach the capabilities of the so-called professional amplification systems. There has been a relatively recent introduction into the marketplace of a preamplifier capable of providing frequency equalization. However, these systems lack substantially in quality and even though they provide equalization facilities, they are severely limited in their versatility.
Heretofore, there has been no amplification system, such as a preamplifier or an integrated amplifier-preamplifier, which provides mixing capabilities for mixing a plurality of input sources and equalization of either the input and/or output sources from the amplification system. Even moreso, the commercially available systems which even do provide for preamplification and equalization are severely limited in that they do not provide facilities for selection among various sources, dubbing from various channels, and the like.
It is, therefore, the primary object of the present invention to provide an audio fidelity amplification system which is capable of providing both amplification, mixing of selected individual input sources, and independent equalization of the frequencies in each of the channels.
It is another object of the present invention to provide an amplification system of the type stated which is constructed with a high degree of quality and is capable of rendering the desired outputs on a relatively low distortion free level.
It is a further object of the present invention to provide an amplification system of the type stated which is highly reliable in its construction and which can be constructed at a relatively low cost.
It is an additional object of the present invention to provide a preamplifier as well as an integrated amplifier-preamplifier combination which is capable of substantially reducing the effect of hum and other electrical noise resulting from low level switches in the amplification system.
It is also an object of the present invention to provide an amplification system of the type stated which is capable of handling various inputs of a wide dynamic range and rendering outputs with a very low distortion factor and which are relatively noise-free.
With the above and other objects in view, my invention resides in the novel features of form, construction, arrangement and combination of parts presently described and pointed out in the claims.